This invention relates to dispensers of the type suitable for dispensing controlled amounts of viscous and semi-viscous materials, such as soaps, hand cleaners and lotions. But, may also be used to dispense other viscous and semi-viscous materials, such as condiments including mustard and catsup. Applicant is aware of the following U.S. patents the disclosures of which are incorporated by reference herein: U.S. Pat. Nos. 847,722; 920,931; 1,164,754; 1,174,674; 1,187,474; 1,392,601; 1,844,557; 2,233,818; 2,283,529; 2,554,570; 2,772,817; 2,814,419; 3,142,415; 3,828,985; 4,085,867; 4,155,587; 4,168,022; 4,222,501; 4,315,582 and 4,515,294
Controlled portion dispensers such as dispensers for soaps, lotions and hand cleaners and other viscous and semi-viscous materials are found in many places. Commonly, they are found in washrooms and repair shops, for dispensing hand soaps and hand cleaners. Typically these devices are wall mounted and may be operated by a lever or a piston to dispense the controlled amount of material. Numerous dispensing mechanisms have been employed to facilitate the dispensing of soaps and similar material, but typical prior devices have the drawback that they are either very expensive or that the reliability suffers in long operation.
It is important that such dispensing continue to operate reliably with long use. Many dispensers fail in use by clogging or jamming in long service due to the accumulation of dry or hardened material in the device or by damage as a result of corrosion or abuse. As a result many of these devices may require repair or replacement which increases the expense of using the particular system. Applicants' have produced a dispensing system for viscous and semi-viscous materials which is highly reliable in long service and in addition is sufficiently inexpensive that it may be discarded and replaced so inexpensively that there is little cost or inconvenience in replacing the mechanism even when failure does occur. Applicants' device may be so inexpensive that it is substantially disposable, for example, with each container of liquid.
Applicants' have obtained this result by producing a small, inexpensive dispensing pump mechanism which fits into the body of a standard screw cap for a soap container or container for other liquid materials. These screw cap bodies typically have a diameter from about 11/2 to 21/2 inches. This presents a serious design obstacle, since the space in which applicants' device can be incorporated, using this design constraint, is quite small. The portion of material dispensed is limited by the volume of the dispensing pump. Applicants have been able to utilize this very small space by producing a pump mechanism which has the internal volume free of obstruction by the mechanism of the pump. Essentially all of the internal volume of the pump mechanism can be used to contain and dispense the viscous material. Applicant achieves this capacity by a uniquely designed mechanism which positions the pump operating mechanism, such as valves, outside of the dispensing and pumping chamber, as is more fully described herein.
Consequently, it is an object of the present invention to provide a dispensing mechanism which dispenses a pre-determined amount of viscous or semi-viscous material upon each activation.
It is a further object of the invention to provide a dispensing mechanism which is easy to use, low in cost and can be readily replaced or retrofitted to existing dispensers.
It is an object of applicants' invention to provide a dispensing mechanism which is unobstructed by the operating parts of the device.
It is an object of applicants' invention to provide an inexpensive, reliable and readily replaceable dispensing mechanism.
It is an object of applicants' invention to provide an inexpensive dispensing pump mechanism which fits within a standard screw cap body.
It is a further object of applicants' invention to provide a dispensing pump mechanism which resists jamming, clogging or failure of continued service.
It is an object of applicants' invention to provide a dispensing pump mechanism which works to dispense measured quantities of a wide variety of viscous and semi-viscous liquids.
Other objects and features of applicants' device will be apparent from the following Description of the Drawings and Description of the Preferred Embodiments.